Verification of live load distribution factors by field testing and analysis

• Autorzy: Eom, J. , Nowak, A.
• Konferencja: VIII Konferencja Naukowa pt. Połączenia i węzły w konstrukcjach metalowych, Olsztyn - Łańsk, 16-19 października 2003
• Języki publikacji: EN

Abstrakty

EN

The paper deals with distribution of truck load on girder bridges. Previous analytical studies based on Finite Element Method (FEM) indicated that the code specified (AASHTO 2003) girder distribution factors (GDF) are inaccurate. In particular, they appear to be conservative for longer spans and larger girder spacing, but too permissive for short spans and girder spacings. Therefore, a field testing program was carried out including 17 steel girder bridges with spans up to 45 m. For each tested structure, girder distribution factors were determined by measuring strains in the girders under heavy trucks. Test trucks were 11 axle vehicles, loaded to the legal limit in Michigan (over 650 kN). The strains were recorded for a single truck, and for two trucks side-by-side. The tests were repeated for crawling speed and normal traffic speed for the location. In all tested bridges, the GDF's determined from the field measurements are lower than code specified values. In addition, the considered bridges were analyzed using a commercial finite element software package, ABAQUS. The analytical results were compared with those from field tests. It was observed that the maximum values of the strain and corresponding stress are lower than analytical values obtained using ABAQUS. The reason for this discrepancy is unintended composite action and partial fixity of supports (rather than simple supports).

Słowa kluczowe

PL

most belkowy; obciążenie; warunki brzegowe; badanie polowe; metoda elementów skończonych; analiza

EN

bridges; truck load; boundary conditions; field testing

• Czasopismo: Konstrukcje Stalowe
• Rocznik: 2003
• Tom: nr 5 spec.
• Strony: CD-CD
• Opis fizyczny: -ROM, s. 161--170, Bibliogr. 12 poz., il.

Twórcy

autor

Eom, J.

• University of Michigan, Dept. of Civil Envir. Engrg., Ann Arbor, Michigan, USA

autor

Nowak, A.

• University of Michigan, Dept. of Civil Envir. Engrg., Ann Arbor, Michigan, USA

Bibliografia

• [1] AASHTO LRFD Bridge Design Specifications (1998). American Association of State Highway and Transportation Officials. Washington, D.C.
• [2] AASHTO Standard Specifications for Highway Bridges (2002). American Association of State and Transportation Officials, Washington, DC.
• [3] Bakht, B., and Jaeger, L. G. (1990): Bridge Testing-A Surprise Every time. Journal of Structural Engineering. ASCE, 116(5), 1370-1383.
• [4] Kim, S-J. and Nowak, A.S (1997): Load Distribution and Impact Factors for I-Girder Bridges. Journal of Bridge Engineering, ASCE, 2(3) 97-104.
• [5] Nowak, A.S., Eom, J. and Sanli, A. and Till, R (1999): Verification of Girder Distribution Factors for Short-Span Steel Girder Bridges by Field Testing. Transp. Research Record , No. 1688, 62-75.
• [6] Zokaie, T., Osterkamp, T.A., and Imbsen, R.A. (1991): Distribution of Wheel Loads on Highway Bridges. National Cooperative Highway Research Program Report 12-26, Transportation Research Board, Washington, D.C.
• [7] Ghosn, M., Moses, F., and Gobieski, J. (1986): Evaluation of Steel Bridges Using In-Service Testing. Transportation Research Record No. 1072,. 71-78.
• [8] AASHTO Guide Specifications for Strength Evaluation of Existing Steel and Concrete Bridges (1989). American Association of State and Transportation Officials, Washington, DC.
• [9] ABAQUS User’s Manual-version 5.6. (1996). Hibbit, Karlsson & Sorenson, Inc., Pawtucket, Rhode Island.
• [10] Tarhini K.M and Frederick, G. R. (1992): Wheel load distribution in I-girder highway bridges. Journal of Structural Engineering, ASCE, 118(5), 1285-1294.
• [11] Bakht, B., and Jaeger, L. G. (1988): Bearing Restraint in Slab-on-Girder Bridges. Journal of Structural Engineering, ASCE, 114 (12), 2724-2740.
• [12] Schultz, J.L., Commander, B., Goble, G.G., Frangopol, D.M. (1995): Efficient Field Testing and Load Rating of Short and Medium Span Bridges. Structural Engineering Review, 7(3) 181-194.